Problem: What is the amplitude of $h(x)=-5\cos\left(2\pi x+5\right)-2$ ?
Solution: Amplitude in sinusoids of the form $f(x)=a\cos(bx+c)+d$ The amplitude of a sinusoid of the form $f(x)={a}\cos(bx + c) + d$ is equal to $|{a}|$. [How can we justify this given our graphical understanding of amplitude?] Finding the amplitude The amplitude of $h(x)={-5}\cos\left(2\pi x+5\right)-2$ is $|{-5}|=5$.